Pneumatic tire

ABSTRACT

A cordless pneumatic tire built on a conventional tire building drum by placing an extruded piece of uncured rubber, including tread and sidewall compounds, between a pair of beads positioned on a pair of rubberized strips, with reinforcing cords, disposed in parallel relation around the building drum. The ends of the strips extending beyond the beads, are reversely turned back over the beads into contacting, adhering relation with the sidewall stock, forming an uncured tire body, which is then removed from the building drum, placed in a mold and heated to vulcanize the tire.

United States Patent on Gordon l l Nov. 11, 1975 l l PNEUMATIC TIRE [75] Inventor: Robert E. Gordon, Toronto. Canada [73] Assigncci The Goodyear Tire 6; Rubber Company of Canada. Ltd., Toronto. Canada 22 Filed: Nmp22. 1972 211 Appl. No.:308,9l3

Related US. Application Data [(33] COHliHULllltil] ol Scri No 84.072 Oct. 18. I970.

abandoned [52] U.S. Cl. 56/123: Lib/I29. l56/l3lll l56/l32; l5fill35; l5l 33l) R: 152/354; 264/326 [SI] Int. Clf" I i I I I BZ9H l7/22; BZ JH l7/26 [58] Field of SearchmW. lib/40L 156.405, Ill) R. I56/IIU Cl- I13. I28 R. l2). It l) I32, I33. Ill I35 [56] References Cited UNITED STATES PATENTS 1380485 (i/lUbN Htirrimn ct ;d. v. ISM I l (l 3503.829 BHWII Muncll ct at... iimJol .bl5.)N7 Ill/IJ7l Blut! cl all .M l5hl l F3 XHUXAITB MlFl-l Bzir\\cll.. lib 4H5 FOREIGN PATENTS OR APPLICATIONS I 1.554 IJl-l lfnitud Kingdonr... l5: l3

Primary li.\umim'rClifton B. Cosln Ant/rm .lucnl. or 1"(1'111F. W, Brunncr; H. E, Hummcr [5 7] ABSTRACT A cordless pncumatic tirc built on a conventional tirc building drum b placing an extruded piucc of un cured rubber. including trend and sidewall conr pounds. between a pair of beads positioncd on ti pair of rubberized strips with reinforcing cords, di g d in parallel relation around the building drum. The ends of the strips cxtcnding bqond thc beads. are rc- \crscl turned back over the bcdds into contacting adhering relation with the -s'idcn'all stock. forming Ltli uncured tirc bod which is then rcmowd from tho building drum. pluccd in a mold and heated to \ulc;| nizc the tire.

3 Claims. 2 Drawing Figures US. Patent Nov. 11,1975 Sheetl0f2 3,919,024

INVENTO ROBERT E. GOR

ATTORNEY U.S. Patent Nov. 11,1975 Sheet2of2 3,919,024

2 INVENTOR.

ROBERT E. GORDON BY am ATTORNEY PNEUMATIC TIRE This is a Continuation, of application Ser. No. 84,672 filed Oct. 28. I970 now abandoned.

BACKGROUND OF THE INVENTION Cordless pneumatic tires built in accordance with the invention, are particularly well suited for use on lightweight amphibious type vehicles employing flotation tires. Such vehicles are generally not equipped for traveling at high speeds and, consequently, strips of tread, or composite strips of tread and sidewall material, without reinforcing cords, can be utilized for forming the tire.

Some flotation tires presently used, are integrally formed and curved on specially designed wheel rims, and do not employ beads. Moreover, distinct and sometimes unusual tire building methods must be employed for building and vulcanizing such tires. The invention is directed to utilizing existing equipment and conventional flat-band tire building techniques, i.e. succes sively wrapping or layering pieces of tire building material around a cylindrical tire building drum, for producing a cordless tire suitable for mounting on conventional wheel rims.

Briefly stated, the invention is in a cordless pneumatic tire and tire building method. The molded and cured tire comprises a pair of beads and trap strips that partially wrap around the beads and trap the beads against the sidewalls of an extruded piece of tread and sidewall material. Trap strips are strips of material including cords, filaments, or laminates composed of cotton, rayon, polyester, plastic. glass, rubber, metal or any other suitable reinforcing material.

The method of building the tire includes the steps of placing the following material around a cylindrical tire building drum: (I) a pair of trap strips in predetermined parallel relation; (2) a pair of beads on the trap strips intermediate the lateral edges of the strips; and (3) an extruded piece of uncured material, including the tread and sidewalls, between the beads in contacting relation with the portions of the trap strips between or inside the beads. The portions of the trap strips outside the beads are reversely folded back over the beads into bead-tying engagement with adjacent exposed faces of the sidewalls. The generally cylindrical uncured tire body is then removed from the building drum, placed in a mold and cured. A gas impervious innerliner, if desired, is first positioned on the drum, after which the trap strips are placed in parallel, completely overlapping relation around the innerliner adjacent the lateral edges thereof.

DESCRIPTION OF THE DRAWING The following description of the invention will be better understood by having reference to the annexed drawing, wherein:

FIG. I is a cross-section of a cordless pneumatic tire made in accordance with the invention; and

FIGS. 2A-2F are schematic illustrations of the building of a cordless pneumatic tire body suitable for molding and vulcanizing.

DESCRIPTION OF THE INVENTION Referring more particularly to FIG. I there is shown a molded and cured cordless pneumatic tire, generally indicated at 6, having a conventional toroidal configuration. The tire 6 comprises a tread 7 and a pair of sidewalls 8 and 9 extending from the tread 7 and interlockingly engaging a pair ofannular beads I0 and I I, which are preferably composed of metal. eg. uncoated. or zinc or brass-coated steel wire. The tire 6 is symmetrical about a plane passing through the mid-circumferential centerline of the tread 7, such plane being referred to as the centerplane (CP). Conventional textile cords extending from bead to bead, are not employed for reinforcing the tread 7 and sidewalls 8 and 9 of the tire 6.

The tread and sidewalls, prior to molding. are formed from an uncured piece of elastomeric material, eg. natural or synthetic rubber. The piece of rubber can be extruded from any suitable tread compound. or composite tread and sidewall compounds which are compatible. It is desirable that the rubber compound or compounds, whichever the case. have a high curing rate to keep molding costs at a minimum. Moreover, the compound, when cured, should be sufficiently strong, such that the tires can be produced with minimum gauges adequate to support vehicles in operation and contain air pressures required for setting the beads on the wheel rims.

A pair of trap strips 12 and I3 partially surround the beads 10 and II and extend into the tire body adjacent inner and outer faces 14 and 15 of the sidewalls 8 and 9. The trap strips 12 and 13 are provided for trapping or securing the beads I0 and II to the adjacent sidewalls 8 and 9. The trap strips I2 and I3 are composed of any suitable material, as previously described, and are preferably coated with any appropriate elastomeric material, e.g. any gum rubber I6 compatible with the other material of the tire 6. The gum rubber 16 extends beyond the lateral edges 17 and 18 of each of the trap strips I2 and 13 and produces a highly improved tie-in of the trap strips. The extensions of the gum rubber 1 6 also acts to prevent separation of the trap strips 12 and 13 from the sidewalls 8 and 9. The trap strips I2 and 13 overlap the sidewalls 8 and 9 a distance sufficient to provide a good interlock between the strips and sidewalls.

A separate gas impervious innerliner 19 is preferably used to seal the inner walls 20 of the tire 6, and can be formed of any suitable elastomeric material, e.g. any rubber compound compatible with the other materials used to form the tire. The innerliner 19 may be incorporated with the trap strips I2 and I3 to form a composite innerliner with trap strips adjacent its lateral edges.

BUILDING THE CORDLESS TIRE Referring more particularly to FIGS. 2A-2F, there is shown a conventionally designed expansible building drum 2! on which flat-band building methods are employed for constructing the tire 6. In the embodiment shown, an innerliner I9 is first wrapped in cylindrical relation around the building drum 2I (FIG. 2A). The trap strips I2 and 13, including coatings of gum rubber I6, are then positioned in at least partially, and preferably completely, overlapping relation around the innerliner I9 adjacent its opposing lateral edges 22 and 23 (FIG. 28).

An intermediate portion 24 of the building drum 2]. is expanded to form a pair of shoulders 25 and 26 in the trap strips I2 and 13 for seating engagement against a pair of wire beads 10 and II moved into position around the building drum 21 (FIGS. 2C-2D).

An extruded piece 27 of uncured tread compound, or tread and sidewall compound. is placed in surrounding relation against the innerliner l9 and trap strips 12 and 13 intermediate the wire beads 10 and 1] (FIG. 2E), The portions 28 and 29 of the trap strips 12 and 13 outside the wire beads 10 and 11, and the lateral edges 22 and 23 of the innerliner l9, are reversely turned back over the beads and compressed in overlapping relation against the outer faces of the sidewalls 8 and 9. A pair of rollers 30 and 31 are used to stitch down the trap strips 12 and 13 and lateral edges 22 and 23 of the innerliner 19 against the adjacent outer exposed faces l5 of the sidewalls 8 and 9. Thus, the adjacent edges 32 and 33 of the sidewalls 8 and 9 are trapped or sandwiched firmly between the trap strips 12 and 13.

The building drum 21 is then collapsed and the intermediate portion 24 returned to its unexpanded position, such that the uncured tire body can be removed from the building drum 2] for placing in a conventional mold, which is then heated to vulcanize the rubber material and form the finished tire 6.

Thus. there has been provided a new and novel cordless tire and tire building method. Conventional tire building techniques are used for producing the tire which, except for the trap strips securing the beads to the sidewalls. does not have conventional tire cords extending from head to bead for reinforcing the tread and sidewalls of the tire.

While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.

What is claimed is:

I. A method of building a pneumatic tire, comprising the steps of:

a. wrapping an air-impervious innerlinner of rubber material around a cylindrical tire building drum at least once;

b. wrapping a trap strip around each of the opposing ends of the innerliner at least once. the width of each of the trap strips measured parallel to the longitudinal axis of the drum being narrow compared to the correspondingly measured width of the innerliner, the trap strips including rubberized reinforcement cords and at least partially overlapping the ends of the innerliner;

c. positioning a pair of annular beads around the trap strips intermediate opposing ends thereof and reversely turning the farthest spaced free ends of the trap strips at least partially around the beads to secure the beads to the innerliner;

d. wrapping a piece of cordless, unvulcanized rubber material around the innerliner between the beads, the material forming the tread. sidewalls and any carcass plies of the tire and being in contact with the innerliner and trap strips, the trap strips material and beads forming a cylindrically shaped unvulcanized tire;

e. removing the unvulcanized tire from the tire build ing drum;

f. torodially shaping the unvulcanized tire; and

g. molding and vulcanizing the torodially shaped tire.

2. The method of claim 1, wherein the cords of the trap strips are composed of material selected from the group consisting of cotton, rayon, nylon, polyester, glass fibers and metal.

3. The method of claim 1, which includes extruding the piece of cordless unvulcanized rubber material forming the tread, sidewalls, and any carcass plies,

prior to placing it around the innerliner.

l l k 

1. A METHOD OF BUILDING A PNEUMATIC TIRE, COMPRISING THE STEPS OF: A. WRAPPING AN AIR-IMPERVIOUS INNERLINNER OF RUBBER MATERIAL AROUND A CYCLINDRICAL TIRE BUILDING AT LEAST ONCE B. WRAPPING A TRAP STRIP AROUND EACH OF THE OPPOSING ENDS OF THEINNERLINER AT LEAST ONCE, THE WIDTH OF EACH OF THE TRAP STRIPS MEASURED PARALLEL TO THE LONGITUDINAL AXIS IF THE DROM BEING NARROW COMPARED TO THE CORRESPONDINGLY MEASURED WIDTH OF THE INNERLINER, THE TRAP STRIPS INCLUDING. RUBERIZED REINFORCEMENT CORDS AND AT LEAST PRTIALLY OVERLAPPING THE ENDS OF THE INNERLINER, C. POSITIONING A PAIR OF ANNULAR BEADS AROUND THE TRAP STRIPS INTERMEDIATE OPPOSING ENDS THEREOF AND REVERSELY TURNING THE FARTHER SPACED FREE ENDS OF THE STRIPS AT LEAST PARTIALLY AROUND THE BEADS TO SECURE THE BEADS TO THE INNERLINER, D. WRAPPING A PIECE OF CORDLESS, UNVULCANIZED RUBBER MATERIAL AROUND THE INNERLINER THE BEADS, THE MATERIAL FORMING THE TREAD, SIDEWALS AND ANY CARCASS PLIES OF THE TIRE AND BEING IN CONTACT WITH THE INNERLINER AND TRAP STRIPS, THE TRAP STRIPS MATERIAL AND BEADS FORMING A CYLINDIRICALLY SHAPED UNVULCANIZED TIRE, E. REMOVING THE UNVULANIZED TIRE FROM THE TIRE BUILDING DRUM, F. TORODIALLY SHAPING THE UNVULCANIZED TIRE, AND G. MOLDING AND VULCANIZING THE TORODIALLY SHAPED TIRE.
 2. The method of claim 1, wherein the cords of the trap strips are composed of material selected from the group consisting of cotton, rayon, nylon, polyester, glass fibers and metal.
 3. The method of claim 1, which includes extruding the piece of cordless unvulcanized rubber material forming the tread, sidewalls, and any carcass plies, prior to placing it around the innerliner. 